Removing X-Fi muting transistors.
Having transistors in the audio loop is definitively a big NO-NO, just go ask any audiophile of Hi-Fists and he did not even need to be an extreme one to tell you this. So, I concentrated my efforts this way. First I produced this picture of what is short direct contact on my X-Fi Fatal1ty:
http://i232.photobucket.com/albums/e...ps_outputs.jpg
And todays I go deeper. It is same for each output. After opamp, there is a 33ohm resistor to protect the opamp from shortcut on the end. It has minimal impact on the signal, so, keep it. Later there are two muting transistors, for the positive and negative flow:
And after them a two small caps to the ground to kill the possible high frequency interference. For L and R channels the card utilize 4 separate transistors. For the rest a dual transistor is used to save space - two (or coudl that be four?) ones in one.
Regardless, the removal is rather easy. First get rid of them:
Then solder a shorts there:
...and you are free to test them. As you probably noticed, I for the work desolder the C46 and C27. And also as you sure noticed, I replaced the LM4562 opamps with AD8599 ones.
The results.
After hearing the sound, I was like "Holly ****...!"
There is no words to describe how much better it sounds. The oversharped thick sound of the LM4562 is gone (LM4562 also like to pick a lot RFI) and the sound is rich and full - and yet more detailed - very likely thanks to these muting transistors removed!
Fantastic change, damn I'm glad I did it!
Side-effects.
As everything in life, there is a price for this. Not only this is NOT easy mod (do NOT try that, unless you are soldering MASTER, and I'm not kidding) but it also has consequences. Not only you want to delete all, even the 320kBi mp3 files now, but upon the driver loading in windows boot, there is notable click in the speakers. Same when changing audio mode. Not louder that the amp is set for, so a minor price for such wonderfull, rich sound.
There is a bigger price and I was quick to discover it.
I remember it well from measuring the voltages on the caps on X-Fi. When I touch the opamps, well, then the X-Fi started to oscilate like MAD and the resulting sound noise, even on small testing speakers, are unbearable.
So, to get to it - I plug my rear speakers into the SUB/CENTER jack, so upon discovering that, I was like fixing this. So I unplug the jack... and the moment it started. The X-Fi, no longer protected with these muting transistors, start oscilating like mad. From all 6 speakers it output SO horrible noise and SO strong, that it was like when F18 is about to land on your head.
I can't remember anything comparable in my life.
My stepbro run to my room asking What... so you get the picture.
The oscilating noise, when you change your speakers, does not stop till reboot.
For me it is fair price to pay. I just can't now hotplug the speakers of fiddle with them "on the fly", like I used to. This is kinda sad and limiting, but what one can do. I'm ceratainly not going to put these cursed transistors back, no way. I love the sound now
way too much.